<!doctype html>
<meta charset="utf-8">
<title></title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
test(function() {
    var style = document.documentElement.style;
    style.marginTop = "0";
    assert_equals(style.marginTop, "0px");
    style.margin = null;  // This used to fail to unset a bit in a LonghandIdSet
    assert_equals(style.marginTop, "");
    style.marginTop = null;  // This would find the bit and expect to find a corresponding declarations.
}, "regression for bug 1345483")
</script>
